1. Field of the Invention
The present invention relates to a life span meter system for a light source used in an electronic endoscope.
2. Description of the Related Art
As is well known, an electronic endoscope comprises a flexible conduit and a video-signal processing unit to which the flexible conduit is detachably joined at its proximal end. The flexible conduit includes an objective lens system provided at the distal end thereof, and a solid image sensor, such as a CCD (charge-coupled device) image sensor, associated therewith. The flexible conduit also includes an optical light guide extended therethrough and formed as a bundle of optical fibers, and the optical light guide terminates at a light-emitting end face at the distal end of the flexible conduit.
Further, the video-signal processing unit includes a light source, such as a xenon lamp, a halogen lamp or the like. When the flexible conduit is joined to the video-signal processing unit, the proximal end of the optical light guide is optically connected to the light source. Thus, an object to be photographed is illuminated by light rays emitted from the distal end of the optical light guide of the flexible conduit, and is focused on a light-receiving surface of the CCD image sensor.
The focused optical image is converted into a series of analog image-pixel signals by the CCD image sensor 14, and the series of analog image-pixel signals are fed to the video-signal processing unit in which the image-pixel signals are processed so as to produce a video signal. Then, the video signal is fed to a monitor, and then the photographed image is reproduced on the monitor on the basis of the video signal.
In general, the light source, such as the xenon lamp, the halogen lamp or the like is a consumption article, and thus must be periodically exchanged with a new one as the lamp in use gradually deteriorates. However, it is difficult to timely know an optimal point when the lamp should be exchanged with a new one. Thus, the video-signal processing un it is provided with a lamp life span meter, so that a remaining life span of the lamp is indicated by a mercury column. Consequently, it is possible to know the optimum point at which the lamp in use should be with the new lamp.
Nevertheless, the utilization of the life span meter is prohibited due to the occurrence of environmental pollution from the mercury used in the life span meter when the video-signal processing unit is treated as industrial waste.
Also, conventionally, for reproduction of a photographed image as a color image, for example, an RGB field sequential type color imaging system is utilized in the electronic endoscope. In this case, it is necessary to periodically perform an adjustment of a white-balance over the span of a life of the lamp, before the color image can be reproduced with a high quality color balance. Nevertheless, there is little likelihood that the life span meter is watched by an operator or doctor to timely know when the adjustment of the white-balance should be performed, because the life span meter is frequently attached at a location of the video-signal processing unit, which is not conveniently observable by the operator or doctor. For example, the life span meter is frequently located on a rear side of a housing of the video-signal processing unit.
Therefore, an object of the present invention is to provide a life span meter system for a light source used in an electronic endoscope that will not cause environmental pollution on disposal.
Another object of the present invention is to provide a life span meter system as mentioned above, in which it is possible to timely and surely announce a point at which the light source in use should be with a new light source.
Yet another object of the present invention is to provide a life span meter system as mentioned above, in which it is possible to timely and surely announce a point at which the light source in use should be with a new light source, and also a point at which an adjustment of a white-balance should be performed.
In accordance with the present invention, there is provided a life span meter system for a light source used in an electronic endoscope, comprising a counter that numerically determined a lit-time of the light source as a numerical lit-time data when the light source is turned ON, a memory that stores the numerical lit-time data as a total numerical lit-time data of the lit-time of the light source when the light source is turned OFF, a determiner that determines whether the total numerical lit-time data reaches a numerical life span data numerically determined from an expected life span of the light source, and an indicator that indicates the light source should be exchanged with a new light source when it is determined by the determiner that the total numerical lit-time data exceeds the numerical life span data.
Preferably, the counter comprises a subtraction-counter initially setting the numerical life span data to an initial value, and subtracting the numerical lit-time data from the initial value. In this case, the initial value of the subtraction-counter, from which the numerical lit-time data is subtracted, is stored in the memory, and the determiner determines whether the initial value of the subtraction-counter, from which the numerical lit-time data is subtracted, is less than zero, and the indicator indicates that the light source should be exchanged with the new light source when it is determined by the determiner that the initial value of the subtraction-counter is less than zero.
The life span meter system may further comprises a detector that detects an exchange of the light source with the new light source, wherein the numerical life-span data is numerically determined from the expected life span of the light source when the exchange of the light source with the new light source is detected by the detector.
Preferably, the detector comprises a light-source-exchanging-signal generating circuit incorporated in a light-source-mounting mechanism in which the light source is detachably and exchangeably mounted, the light-source-exchanging-signal generating circuit is arranged so as to outputs a light-source-exchanging signal, indicating that the exchange of the light source with the new light source has been performed, when a mounting of the new light source in the light-source-mounting mechanism is completed and when the electronic endoscope is electrically energized.
The light-source-exchanging-signal generating circuit may be formed as a switching circuit including a voltage-applied electric line, a grounded electric line, and a movable electric contact which is arranged such that an electrical contact is established between the voltage-applied electric line and the grounded electric line when the mounting of the new light source in the light-source-mounting is completed, resulting in the outputting of the light-source-exchanging signal.
Preferably, the light-source-mounting mechanism includes a movable light-source mounting plate for mounting the light-source, a movable switching plate member, carrying the electric contact, associated with the light-source-mounting plate such that the switching plate member is moved in accordance with a movement of the light-source-mounting plate, and a locking unit for locking the switching plate member at a predetermined position during a movement of the switching plate member by the light-source mounting plate, the electrical contact being established between the voltage-applied electric line and the grounded electric line when the switching plate member is positioned and locked at the predetermined position by the locking unit.
The switching plate member may be provided with a spring unit which is arranged so as to be subjected to a compression when the switching plate member is positioned and locked at the predetermined position by the locking unit, the switching plate member being moved from the predetermined position due to the compression of the spring unit so that an electrical disconnection is established between the voltage-applied electric line and the grounded electric line when being unlocked by the locking unit.
The span meter system may further comprises another In indicator that indicates an initial adjustment of a white-balance should be performed when the exchange of the light source with the new light source is detected by the detector.
The life span meter system may further comprises yet another indicator that indicates a readjustment of a white-balance should be performed when the numerical lit-time data reaches a multiple of a pre-set numerical data over a period of said numerical life span data.